Web pickup arrangement for papermaking machines

ABSTRACT

Web pickup arrangement for Fourdrinier type papermaking machine in which the forming wire changes it direction about a couch roll from the forming run thereof to a pickup run and travels angularly downwardly and rearwardly from the off-running side of the couch roll about a downwardly and rearwardly spaced contact roll, maintaining a tensioned downwardly facing pickup run of the wire. The downwardly facing pickup run of the wire extends tangentially of a pickup roll picking the web from the wire for transfer along a press felt through the press rolls of the machine.

1973 I K. N. MAITRA 3,708,389

WEB PICKUP ARRANGEMENT FOR PAPERMAKING MACHINES Filed Dec. 2. 1968 INVENTOR. KuM/ne A! Mar/e4 w W APTOAWMS United States Patent O ice 3,708,389 WEB PICKUP ARRANGEMENT FOR PAPERMAKING MACHINES Kumar N. Maitra, Beloit, Wis., assignor to Beloit Corporation, Beloit, Wis. Filed Dec. 2, 1968, Ser. No. 780,487 Int. Cl. D21f 2/00 US. Cl. 162306 4 Claims ABSTRACT OF THE DISCLOSURE Web pickup arrangement for Fourdrinier type papermaking machine in which the forming wire changes its direction about a couch roll from the forming run thereof to a pickup run and travels angularly downwardly and rearwardly from the off-running side of the couch roll about a downwardly and rearwardly spaced contact roll, maintaining a tensioned downwardly facing pickup run of the wire. The downwardly facing pickup run of the wire extends tangentially of a pickup roll picking the web from the wire for transfer along a press felt through the press rolls of the machine.

SUMMARY AND OBJECTS OF THE INVENTION Pickup for fibrous webs, which may be adapted for heavy and lightweight sheets in high speed papermaking, in which the Fourdrinier wire is trained to provide a downwardly facing pickup run carrying the web for transfer to a pickup roll, extending tangentially of the pickup run of the web.

A principal object of the invention is to provide an improved form of pickup arrangement for papermaking machines facilitating the pickup of a web from the forming wire, by picking the web from a downwardly facing pickup run of the wire,

A further object of the invention is to provide a simple and improved form of pickup for Fourdrinier type papermaking machines, adapted for various weights of sheets, in which the pickup efficiency is increased by picking the web from a downwardly facing side of the forming wire and transferring the web along the top surface of a press felt, carrying the web through the usual press rolls.

Another object of the invention is to improve upon the pickup of a newly formed web or sheet from the Fourdrinier wire, by training the wire about the couch roll along a downardly facing pickup run, and utilizing a suction roll, to pick the web from the downwardly facing pickup run of the wire, in which a press felt trained about the suction roll carries the web with outer surface of the web facing the bottom surface of the press felt.

Another and important object of the invention is to improve upon the transfer of a sheet or web from the Fourdrinier wire of a papermaking machine, by engaging a downwardly facing web pickup surface of the wire forming wire with a pickup roll, picking the web from the roll by suction, and transferring the web from the pickup roll along a press felt by a transfer roll, changing the direction of the felt to travel along its press urn generally tangentially of the pickup roll with the wire surface of the wire facing the press felt.

These and other objects of the invention will appear from time to time as the following specification proceeds and with reefrence to the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic view of a felt pickup arrangement constructed in accordance with the principles of the present invention, and showing the press felt trained about a pickup roll with the outer surface of the web facing the undersurface of the press felt.

3,708,389 Patented Jan 2, 1973 FIG. 2 is a diagrammatic view of a modified form of the invention in which the press run of the felt carries the web on its top surface between the press nip with the wire surface of the web facing the felt and particularly adapted for light to medium webs or sheets, and

FIG. 3, is a view of a modification of the invention shown in FIG. 2, but showing a pickup and press roll arrangement adapted for medium and heavy weight webs or sheets.

DESCRIPTION OF PREFERRED EMBODIMENTS OF INVENTION In the embodiment of the invention illustrated in FIG. 1 of the drawings, I have shown the discharge end portion of the forming run of a looped Fourdrinier wire 11 changing its direction to a pickup run R about a couch roll 12 defining the off-running or discharge. end of the forming run, and containing the usual suction box or vacuum area 17 removing water from a web or sheet W on the wire. From the couch roll, the wire travels downwardly and rearwardly about a contact roll 15, maintaining the wire under tension and training the wire along a downwardly facing pickup run R, extending tangentially of a pickup roll 16. The couch roll 12 may be of a conventional form having a conventional vacuum area 17 for de-watering the web as it turns about said couch roll and passes along the pickup run R.

A continuous looped pickup felt or fabric 19 is trained under a felt idler 20 and rearwardly therefrom about the pickup roll 16 in contact with the web on the undersurface of the wire. The pickup felt 19 may be a conventional felt or open fabric commonly used for pickup purposes and carries the web about the pickup roll 16 along its undersurface along a press run 21 in the nip between a pair of upper and lower press rolls 22 and 23. The pickup roll 16 is shown as being a vacuum type of pickup roll and has a perforate cover of wire or fabric (not shown). A vacuum area 25 within the perforate cover of said roll cooperates with the felt 19 to pick the web from the downwardly facing felt pickup run R of the Wire and carry the web along the undersurface of the felt with its outer surface facing the felt along the press run thereof, in the nip between the press rolls 22 and 23. The vacuum area 25 may have a high pickup vacuum area and a low holding vacuum area and a lower holding vacuum area.

In FIG. 2 of the drawing, I have shown a modification of the invention, particularly adapted for light to medium weight sheets in which the wire side of the web or sheet is transferred to an upwardly facing press run of a press felt 21.

In this form of the invention, like the form of the invention illustrated in FIG. 1, the web W is carried by a looped Fourdrinier wire about a couch roll 12 and angularly downwardly and rearwardly from the off-running side of said couch roll about a contact roll 15 training the wire into a downwardly facing pickup run R.

The web W is shown as being contacted by a conventional lump breaker roll 27, at the incoming side of the couch roll. The pickup run R of the wire is directly contacted by a pickup 29. The pickup 29 may be wire or fabric covered and has a suction area 30 having communication with the web through the wire or fabric cylindrical peripheral surface of the roll. A shower or cleaner 31 may be spaced circumferentially of the suction area 30 to spray through the roll and keep the surface of the roll clean. The wire or fabric faced pickup roll 29 directly contacts the web on the downwardly facing pickup run R of the wire, while the high and low vacuum suction area 30 transfers the web from the wire to the pickup roll 29. The web in turn is transferred to the felt 32 by a transfer roll 33, training the incoming run of the felt 32 to contact the wire side of the web on the pickup roll 29, and carrying the web along a generally horizontal press run of the felt on the top surface of the felt. The transfer roll 33 is schematically illustrated as being adjustable by the double headed arrow, accommodating a selection of the spacing and pressure between the pickup felt 32 and the web W at the nip between the transfer roll 33 and pickup roll 29. The transfer roll 33 is shown as having a suction area 36 supplying suction to draw moisture from the web and facilitate the transfer of the web from the pickup roll 29 to the press run of the felt 32, along the top surface thereof. The felt 32 carries the web from the pickup and transfer rolls 29 and 33 respectively, in the nip between upper and lower press rolls 39 and 40 respectively, and from said press rolls in the nip between upper and lower press rolls 41 and 42 respectively to and around a direction changing idler 43 training the felt downwardly for cleaning in the basement, and back to the transfer roll 33. The press roll 40 is shown as having a suction area 45 for de-watering the web.

The press roll 42 is diagrammatically illustrated as being a grooved roll which may have an imperforate shell, as described and claimed in the E. J. Justus U.S. Pats. Nos. 3,198,693, 3,198,694, 3,198,695, 3,198,696 and 3,198,697. The grooved roll 42 serves as a de-watering press roll in accordance with the teachings of the foregoing patents, incorporated herein by reference. A water spray 46 is diagrammatically shown as providing the water to maintain the grooves of the grooved roll 42 clean, while a doctor 47 is spaced circumferentially of the water spray 46 in an outgoing direction from the water spray 46.

In the embodiment of the invention just described, all complicated overhead framing for the felt run has been eliminated, the wire side of the web is transferred in direct contact with the felt, and cleaning of the felt can be carried out in the basement.

In the form of the invention illustrated in FIG. 3, the wire 11 is trained about the couch roll 12 and has a downwardly and rearwardly inclined pickup run R like the pickup run in the forms of the invention illustrated in FIGS. 1 and 2 and maintained under tension by a contact roll abount which the felt turns. A lump breaker roll 27 is shown as provided at the incoming side of the couch roll 12, while a saveall 48 extends partially about the couch roll 12 from. the outgoing to the incoming side thereof. The saveall 48 may be of a conventional form and need only be used under operating conditions which are such as would tend to damage the formed web by throwing water thereon.

The web is transferred from the downwardly facing transfer run R of the wire by a pickup roll 29 exactly like the pickup roll shown in FIG. 2 and is transferred from the pickup roll 29 to the upwardly facing surface of the felt 32 by an adjustable transfer roll 33 having a suction area 36.

In this form of the invention, the press rolls 39 and 40 shown in the form of the invention illustrated by FIG. 2 have been dispensed with and a plain surfaced press roll 49 provides a press nip for the felt 32 and web W carried thereby in cooperation with a grooved roll 50, like the grooved roll 42. The grooved roll 50 is shown as being cleaned by a water spray 51 and doctored by a doctor blade 53 on the outgoing side of the water spray 51, as in the form of the invention illustrated in FIG. 2. A felt idler 55 is provided at the outgoing side of the press run to train the felt 32 downwardly for cleaning and return to the suction transfer roll 33.

The pickup of the present invention as illustrated in FIG. 1, forms a positive pickup .of the web from the wire,

readily transferring the web to the press felt to be carried through the press section with the outer side of the web contacting the felt, and with the Wire side of the web carried by the felt as in the form of the invention illustrated in FIGS. 2 and 3. The pickup arrangement by picking up the web from the underside of the wire, thus lends itself to more efliciently picking the web from the wire, is adaptable for various grades of sheets from light to heavy weight sheets and the liability of drop-off of the sheet is reduced to a minimum.

While I have herein shown and described one form in which the invention may be embodied, it may readily be understood that various variations and modifications of the invention may be attained without departing from the spirit and scope of the novel concepts thereof.

I claim as my invention:

1. In a web pickup arrangement for a Fourdrinier type papermaking machine, in combination,

a Fourdrinier wire having a forming run, having a discharge end,

a couch roll defining the discharge end of the forming run,

a contact roll spaced beneath and rearwardly of the couch roll and carrying the wire into a downardly facing pickup run,

a pickup roll disposed along the pickup run of the wire between the couch roll and the contact roll in close running pickup relation with the wire for receiving a web therefrom,

a press felt,

a transfer roll having pressure nip engagement with the pickup roll on the underside thereof,

means training the press felt to travel about said transfer roll in the nip between said pickup roll and transfer roll to transfer the web from said pickup roll.

2. The web pickup arrangement of claim 1, in which the pickup and transfer rolls are suction rolls.

3. The web pickup arrangement of claim 1, including a pair of upper and lower press rolls having pressure nip engagement with each other, and wherein the means training the felt in the nip between said pickup roll and transfer roll includes said press rolls and a direction changing idler spaced from said press rolls on the outgoing sides thereof and training the felt and web to pass in the nip between said press rolls.

4. The web pickup arrangement of claim 3,

wherein the transfer roll is a suction roll and is adjustable relative to the pickup roll.

References Cited UNITED STATES PATENTS 2,694,346 11/1954 Goodwillie 162-306 X 3,285,806 11/1966 Justus et al. 162306 FOREIGN PATENTS 436,005 1/1912 France 162306 270,365 2/1914 Germany 162306 OTHER REFERENCES Pulp and Paper Making Notes, Scott Paper Company, p. 241, 1956 (publishing date), date in Examining Division-at least since 1963.

S. LEON BASHORE, Primary Examiner A. L. CORBIN, Assistant Examiner U.S. Cl. X.R. 162-360, 364 

